An image forming apparatus such as a laser printer includes a toner carrier (e.g. a conveying belt) for conveying sheets, performing intermediate transfer, or the like. This toner carrier can have untransferred toner remaining clinging thereto. This residual toner can give an undesired influence to subsequent image forming operation.
There is a known image forming apparatus that includes a waste collecting device for collecting the waste clinging to the toner carrier. Furthermore, there is an image forming apparatus that further includes a waste detecting unit. The waste detecting unit detects an amount of the waste collected in the waste collecting device reaching a predetermined amount. With this waste detecting unit, overflow of the waste out of the waste collecting device is prevented from occurring.
Specifically, the known waste collecting device has a collection opening and a displaceable member. The collection opening allows the collected waste to enter, while the displaceable member is disposed directly below the collection opening. This displaceable member is displaced according to an amount of the waste accumulated and, by detecting this displacement, it is determined that the waste amount in the waste collecting device has reached the predetermined amount.
Moreover, there is another known waste collecting device that has a collection opening and a waste detecting sensor. The collection opening allows the collected waste to enter, while the waste detecting sensor is disposed near the collection opening. In this art, the waste accumulated directly below the collection opening is detected by the waste detecting sensor and, based on the detection results, it is determined whether or not the waste collecting device is filled with the waste.